MBL March Madness: Chain Catshark

Chain catshark (Scyliorhinus retifer) is a small species of shark that lives in the Atlantic Ocean, the Gulf of Mexico, and the Caribbean. They spend most of their time resting on the seafloor, where they attach pairs of egg cases like these to rocks. The eggs hatch after 8 to 12 months. Scientists at the MBL study the development of catshark eggs to better understand human growth and development. Fish like the catshark were swimming the oceans long before animals with backbones evolved to live on land. The wings of birds and bats, the legs of cheetahs and lizards, and your own hands and feet are all derived from the fins of ancestral fish, which are closely related to sharks and rays. These ancient connections give us a better grasp on how our bodies develop at a cellular level.

Fun facts: 

• The chain catshark possesses biofluorescent properties and under certain light will glow bright green.
• The females release 2 egg cases, or mermaid’s purses, which have long stringy tendrils attached to help the egg case snag on a structure to anchor it.
• They have been found living at depths of 460 meters (1560 feet).